Decorticating of flax and other bast fibers



J. THOMSON Sept. 25, '1945.

DECORTICATING OF FLAX AND OTHER BAST FIBERS Filed April 22, 1942 2 Sheets-Sheet 1 J n Thomson [NV EN TOR Sept. 25, 1945. THC)MSON DECORTICATING OF FLAX AND OTHER BAST FIBERS Filed April 22, 1942 2 Sheets-Sheet 2 John Womson INVENTOE,

Patented Sept. 25, 1945 OFFICE DECOR-TICATING OF FLAX AND OTHER BAST FmERS John Thomson, Paisley, Scotland AppIicationApriLZZ, 1942, Serial-No. 440,033 In Great Britain May 2,1941

8 Claims.

This. invention relates to the. decorticating of flax, whether. retted. or green, and other bast fibers. In this specification and in the appended claims the term straw is used to designate the flax and other stalks which are decorticated;

More particularly the invention relates to a machine in operation of which opposite endsof a length of straw, arranged in a sheet or layer, aregripped. and a. relative reciprocatory motion between the gripping means is effected so that the length of straw is bent first in onedirection and then. in theopposite direction and in this way the strawis decorticated.

An object of the invention is to providean improved. machine for decorticating straw by feedingthe straw through a decorticating zone in av continuous supply spread out in a, wide layer and by repeatedly bending the straw at said zone throughout practically the entire length of every stalk, no. matter how short, in alternately opposite directions.

Another-object of the present invention is to provide an improved machine in which the work of feeding in the strawand the subsequent decortication of it will follow one another as a continuous operation----that is, without interruption by stoppage of the machine.

Another object of the invention is to provide a machine in which the gripping means'aretimed to open. and close in such relation to they relative reciprocatory motion that the length of straw is pulled into position in a' controlled manner for decortication by the action of the machine.

Another object of the invention is to provide feed means to assist the gripping means in their work of pulling the straw into the decortication position.

Another object of the invention is to provide means for withdrawing the straw length by length from the grippers following each. decortication. operation.

Other objects of the invention will be apparent from the following specification and, appended claims.

The. invention is illustrated by the accompanying drawings, in which:

Fig. 1 isa diagram showing the straw grippers and associated-means for feeding-in the straw to be decorticated and for withdrawing, it after decortication. I

Fig. 2 is a diagram of means'for opening and closing one of the grippers.

Fig. 8 is, a similar diagram of meansfor reciprocating and means for opening and closing the'other gripper.

Figs. 4to 8 are a series of diagrams drawn to a smaller scale. than Fig. 1 and showing the grippers and associated means in different positions in the cycle ofoperations. 7

Figs. 9 to 13 show a machine which operates in accordance, with the principles illustrated by the diagrams Figs. 1.to'8. Figs. 9 to 13 are drawn to a smallscale and various of the parts shown are conventionally represented. Of these figures, Fig. 9 is an end elevation of the machine, Fig. 10 Ba plan with upper parts removed for clearness, Fig. 11 is a section on line XI-XI of Fig. 10, and Figs. 12 and 13 are fragmentary sectional elevations approximately on lines XII and XIII, respectively, of Fig. 10.

Throughout. the, several= figures of the drawings, similar parts or corresponding parts are denoted by the same reference characters.

Referring to Fig. 1, the parts therein shown comprise: twopairs of superimposed complementary gripping blocks, the. blocks of the first pair being denoted l4 and I5. and the blocks of the second pair being denoted I6. and I1; an assemblyof: lead-bands, namely a single lower feed. band: l8; and. upper. and lower withdrawal bands. I9 and 20'; and a pair of rollers Z1, Z2 housed and journalled in the blocks l6, l1 and adapted to. supplement the action of lead-bands I9, 20. A layer of straw isdenoted by S. The blocks [4, l5, are spaced apart from the blocks 16. ll. to provide a gap G which is just large enough to afford little more than a working clearance for the decorticating operation, which takes place in the gap. It will be seen that the straw S occupies a horizontal plane where it passes through each pair of gripper blocks and that the gap G extends vertically, i. e. transversely of said plane.

The blocks I4, I 5 are at the feed side of the gap. 'I'heyhave facings I4A, I5A, which are shaped to widen the gap as it recedes upwards and downwards from the gripping plane of each pair of blocks. The blocks I6; ll have face plates ISA; 1A, which close the housing spaces for the rollers 2l, 22'. The lead-bands may be made of linen. The single feed band [8 passes between .the first blocks l4, l5, whereas the upper and lower withdrawal bands l6, I! pass from the gap G between the second blocks l6, l1 andbetween the rollers 2|, 22. These are smooth steel rollers.

The lower block l5 oi the first pair is a permanently stationary fixture, and the complemenper constituted by the blocks l6, I1 is recipro 'catory. Figs. 2 and 3 show how the openingand closing motions and the reciprocatory motion are obtainable.

As shown in Fig. 2, the block l4 hasfulcrumed on it a bellcrank lever 23 which is connected by scending second gripper. In the Fig. 6 position, the pulled-in length of straw is gripped at opposite ends by the grippers. The motion from Fig. 5 to Fig. 6 is the first half-stroke of the cycle, and the decorticating action now starts. This action is effected by the reciprocating second gripper. Fig. '7 shows the second gripper at the top of.its ascent. In theup-and-down motion between the limits shown in Figs. 6 and '7, the central plane of this motion being at the level Where the two grippers are in horizontal alignment, the length of straw is rapidly bent in altera wire 24, a lever 25 and a wire 26 passingoVer a pulley 2! to a cam-lever 28, which'co-operates with a cam 29 on a slow-speed shaft 30 driven by gears 31, 32 from a main driving shaft 33. The levers 25 and 28, the pulley 21 and the shafts 3i and 33 are all turnable or rotatable about stationary axes. One arm of the lever 23 presses down on-a projection 34 onthe stationary lower block 15. A-spring 35,- with a stationary anchorage 36, presses the upperblock l4 towards the lower block, and stationary guides 31 serve for the guidance of the block I4. In operation, when the'hump of the-cam 29 makes contact with the lever 28', the lever- 23 is pulled to force the block 14 upwards against the-pressure ofspring l5. Thus, for a short period in one of every series of revolutions of the driving shaft 33 (say in every eighth revolution) the gripper I4, I5 is opened. When the. cam hump passes the lever 28, the upper block I4 is forced by the spring action to close again on the lower block 15.

As shown in Fig. 3, the lower block I] is reciprocatedbetween stationary guides 38 for both blocks [6,11, by an eccentric 39 which is on the driving shaft 33 and which acts through a connection Won the block l'l. Theopening and closing motion of the upper blockis efiected by cam-action through parts 23.36 similar to those already described with refer'encetoFig-Z except that the fulcrum of lever 25 .and the anchorage 36 are not stationary but are provided on brackets M and respectively secured to the blocks l6 andl'l..* L.

Fig. 1 shows the .parts in. what may be convenientlyregarded, for the purposes of explanation, as the startingposition of the cycle of op erations. In thisposition, the gripping surfaces ofjboth pairs of blocks are co-planar and. both pairs are closed on the straw S. Fig. 4 shows the parts which aremore important .for the purpose of pictorial representation in the same position, less important, parts being omitted from Fig. 4 and the corresponding Figs. 5 to 8 for clearness; and the cycle of operationswill now be described with reference tothese figures.

In the Fig. 4 position, the second gripper assembly (of which;on1y. .the faces, 6A,v HA and rollers 2!, 2 2. are shown) is descending. in its reciprocatory motion, NeXt the first gripper I4,

I 5 is temporarily opened, its upper block .[4 being lifted by the associated cam-mechanism (Fig. .2) The full open position of; the first gripper is shown in Fig. 5. The first gripper closes again by the time that the second-gripper reaches the bottom of its descent, as Fig. 6 shows. During the short period that the first gripper is open, straw S is pushed through it by the momentarily advancinglead-band [8 (Fig. 1) anda length of the straw is pulled into the-gap G by the v Lie-.-

nately opposite directions within the confined space of the gap G. The straw is not only sharply bent to-and-fro, but is also rubbed by the walls of the gap." 'There may be about seven down- .stro'kes andteight-up-strokes imparted to the second gripper in order to perform deoortication completely. At the end of the decorticating action,the second gripper is at the top of its up stroke, asrepresented by- Fig.- 7. During the first half of its next down-strokeiwhich isthe last half-stroke o flthecycle) the second gripper is opened and closed again by the associated cammechanism (Fig.2 3).. .The. second gripper is shown full open .inyFig. 8 aIid'i'is shown closed again in, Fig. 14. Whilst. the'lsecondgripper is open, the lead-bands l9,.20. are-momentarily advanced and the rollers-. 2l,..22.are momentarily rotated to-withdraw thedecorticated length of straw from the gap." r

Thus it will be seen thatiin a cycle .of say sixteen strokes (or eight ;.reciprocations) of the secondgrippenthe time taken by one of these strokes is utilised partly for withdrawing a decorticated length of -straw. and partly forbringing in anewlength and the remainingstrokes areall devoted to the decorticating action.

,In the foregoing description, theilayer of straw S,-has been assumed to extend. from' the feedband l8 and across the decortication gap G to the Withdrawal bands-19,20... vAt the commencemer t of decorticating asupply ofzstraw S,.the straw is merely placed uponthe feedeband l8 andthe-machineis started. The leading .end of the straw: is entered. step-by-step ,through the first gripper by; the stepwise, advancing feedband. The materiahis; pushed against the bands l9,"20, which both form in effectfone wall of the gap. In'each upstroke of the blocks l6 .and I1 constituting the second gripper, the; ungripped end of the straw is bent upwards by;the upgoing second gripben'fsd that atth top of its upstroke the strawis' lying against the band 29 ;on the face of the lower block plate HA; Assume that the second grippe'r'i's due to open during the first half of its nextdoWh'stroke, as Fig. 8 illustrates. As the second gripper descends the blocks is; n constitutingits jaws open and the rollers; 2!, 22 are-rotated to advance thebandslQ, 20, with the result that theband 201now travelling/up wards relative to the block IT maintains the straw end bent upwards until eventually the opening between the blocks "IS; IT, reaches the straw end, and the bands [9,20 as they move between the now closing blocks l6, l1 co-operate to draw the straw e'nd between themselves, so that said end is g rippedfi This {action of gripping .the.end of-abatchof straw fed between the blocks' l l, I5-of' the" firstgripper' takes place surely andspeedily-andautomatically; f

The foregoing description of themain parts according to Figs. inc 8' and of-their cycle'of operation applies fully to themachine according toFJ S. -9. to .13.. These figures serve chiefly to show themachine as a whole andto give .particulars of the mechanism. not shown in the previous figures, namely'Figs. 1 to3, .for operating the moving parts.

Referring to Figs. 9 to 13, theframe of the machinecomprisestwo gables 43, 44' by'which most-of the working parts are supported and between: which the gripper blocks extend, the guides3'l, 38 for the ends of the blocks 14, lfiand I! being provided in these gables, as Figs. 9, 12 and 13 indicate. The block I is a stationary fixture on the gables 43, 44. Theguides38 constrain the movable gripper [6, 11 to rectilinear motion transverse to the horizontal plane of the straw S throughout the operation of the machine.

The main driving'shaft 33 is driven at one or both ends by say a pulley or pulleys 45 and the connections between said shaft and the camshafts 30 comprise toothed gear wheels 32, 3| of gear ratio 8:1. A set of these gear wheels may be provided at each end of the machine, as shown.

The lead-bands 18, I9 and 20 are operatively connected to the gear wheels 3| from which they receive their momentar advance motions in the operation of the machine whilst the respective grippers are open for the feed-in and withdrawal of the straw. These three bands are shown in dotted lines in Figs. and 11.

As shown, the feed band 18 is led around a series of rollers comprising: a roller 46 (Fig. 11) journalled in stationary brackets (not shown) beyond the end of the gables 43, 44; a pair of band-tensioning rollers 41 journalled on a stationary beam A (Fig. 13) below the gables and acted upon by spring-tensioning devices 48 (conventionally represented); and three pairs of rollers 49, journalled in the gables 43, 44, the rollers of each of these pairs gripping the upper straw-receiving stretch of the band [8 at the nips between them. The upper rollers 49 are the only ones in the series which are positively driven. They are connected by a driving chain 50 to a train of gears 55, the endmost of which is on the same shaft as a pinion 52 (see Fig. 9) which receives a small turn from an adjustable striker 53 on the adjacent gear wheel 3| once in each revolution of that gear wheel. That is to say, the feed-band 18 receives its momentary advance motion once in every eight revolutions of the main driving shaft 33.

Each of the withdrawal bands is led around a series of rollers comprising: a band-tensioning roller 54 journalled in the gables 43, 44, the tensioning devices 55 being represented conventionally in Fig. 9; one of a pair of co-operating rollers 55 which are journalled in the gables and which nip both bands between them at the straw-engaging stretch leading from the rollers 2!, 22 (see also Fig. l); and two rollers 51 journailed in brackets 58 secured to the respective gripper block it or ll and acted upon by bandtensioning devices 5t conventionally represented in Fig. 12. There is a chain drive 6!] between the shaft of a driving pinion El and one of the rollers 54; and there is another chain drive 62, through an idler gear 63, between these two rollers. The pinion Si is operated by an adjustable striker (id in the same way as the pinion 52 for the feed band l8. Thus, the withdrawal bands i 9, 2% also receive their momentary advance motion once in every eight revolutions of the main driving shaft 33.

As Fig. 9 indicates, the driving pinion 6| for the withdrawal bands is actuated slightly in advance of the pinion 52 for the feed-band. This is hecause thesecond gripper l6, l1 opens slightly in advance of the first gripper l4, 15 during that stroke of the second grippernamely, during that half-revolution of the main shaft 33-devoted to the advance motions of the straw.

The tensioning devices applied tothe various lead-band rollers allow the respective lead-bands to follow up-and-down movement due tothe passage of the straw anddue to the reciprocatory motion of the second gripper l6, l1. At the delivery zone of the withdrawal lead-bands I9, 20, a table (not shown) maybe provided to receive the decorticated straw as it issues from said lead-bands.

It will be clear that the method of decorticating applied by the operation of the machine hereinbefore described consists in effecting a reciprocatory motion between the gripped ends of a length of straw so as to bend the length of straw repeatedly in alternately opposite directions until it is decorticated. In the following claims the foregoing method is referred to for brevity as a decorticating action.

I claim:

1. A decorticating machine comprising a stationary gripper, means for opening said gripper periodically, a movable gripper spaced from said stationary gripper to provide a decorticating gap, mechanism for reciprocating said movable gripper to perform a decorticating action, means for opening said movable gripper periodically as it reciprocates, straw-feed means leading to said stationary gripper, straw-withdrawal means leading from said gap through said movable gripper, mechanism operatively connected to said stationary-gripper-opening means and timed for operation of said straw-feed means to feed straw to be decorticated through said stationary gripper and push said straw across said gap when said stationary gripper is opened and while said movable gripper is closed, and mechanism operatively connected to said movable-gripperopening means and timed for operation of said strawwithdrawal means to pull decorticated straw from said gap and through said movable gripper when it is opened and while said stationary gripper is closed.

2. A decorticating machine as claimed by claim 1 including also guide means constraining said movable gripper to a rectilinear A movement throughout the operation of the machine.

3. A decorticating machine as claimed by claim 1 in which said stationary gripper is arranged at the level of said straw-feed means, said movable gripper reciprocates between limits above and below said level, and said straw-feed operating mechanism is timed to push in straw while said movable gripper is moving from said level towards one of said limits.

4. A decorticating machine as claimed by claim 1 in which said movable gripper comprises a pair of cooperating blocks and in which said strawwithdrawal means comprises endless bands forming a wall of said gap and passing between said blocks and roller means leading said bands to convey decorticated straw from said gap between said blocks.

5. A decorticating machine as claimed by claim 1 in which said stationary gripper comprises a pair of cooperating blocks and in which said straw-feed means comprises a flat conveyor band passing between said blocks.

6. A decorticating machine comprising a first gripper, means for opening said gripper periodically, a second gripper spaced from said first gripper to provide a decorticating gap, mechanism for effecting a relative reciprocatory motion between said grippers to perform a decorticating action, means for opening said second gripper periodically, straw-feed means leading to said first gripper, straw-withdrawal means leading from said gap through said second gripper, mechanism connected to said first-gripper-opening means and timed for operation of said strawfeed means to feed straw to be decorticated through said first gripper and across said gap when said first gripper is opened and while said second gripper is closed, and mechanism connected to said second-gripper-opening means and timed for operation of said straw-withdrawal means to withdraw decorticated straw from said 10 tween said blocks.

8. A decorticating machine as claimed by claim 6 in which said first gripper comprises a pair of cooperating blocks and in which said straw-feed means comprises a flat conveyor band passing it! between said blocks.

JOHN THOMSON. 

